Teensy 3.2 and Audio board integration schematic verification help needed

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experion

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I would greatly appreciate any help with this schematic. Just want to make sure the connections are correct. I am a bit jaded from looking at it too long.

The board is based on a teensy 3.2 and Audio board. Also added a Lipo charging circuit.

I would like these connections checked for correctness:
  • Bootloader (MKL02Z32VFG4_QFN16) to processor
  • Crystal connection
  • Audio board (SGTL5000) setup and connection to the teensy processor
  • Power regulator (TPS61201) connections.

Thanks for any help in checking this.

Also on the PCB board, is it ok to have only the ground under the Crystal on the other side of the 2 layer PCB.

Schematic Link here
12-11-2015 06-50-50.jpg12-11-2015 06-56-03.jpg

Update:

Changes have been made to the above schematic and the board.
Please check the link and see if there are any errors.

Schematic Updated Link here
 

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Someone please help out. You can just verify one pin at a time. Others can verify the other pins.

Paul I know you are busy, do not want to get it wrong this time.
If there was a way to pay for the service, I would pay for it.
 
This is quite a hefty favour to ask of the community.

Make yourself a check list of all the pin connections from the datasheets. Then run down your circuit and cross off the one's you've made
 
Xenoamor said:
This is quite a hefty favour to ask of the community.

Make yourself a check list of all the pin connections from the datasheets. Then run down your circuit and cross off the one's you've made
Click to expand...


Thanks for your reply:D . I know its a lot to ask. I can pay for the service, if there was a way:cool:. Makes sense to seek help here first since most users are familiar with the teensy and even the teensy audio board.

Will try and do as you suggested. thanks
 
I've never used the Audio board. So I can only comment on what's different from the original design and not what makes sense and what not.

Teensy
Connect all supply/gnd pins from the K20 (30,31,47,48).
no VREF_OUT capacitor (I think it's ok here to not connect VREF_OUT, because you don't use the DAC or ADC.)

On the Audio board (V2):
different cap values: C28, C32
R7, R2 resistors vs caps
pin 5 from the SGTL5000 is connected to 3.3V (through a ferrite bead). On your board it goes to +1.8V.

TPS61201
Connection from/to UVLO and VAUX doesn't look correct.
 
HWGuy said:
I've never used the Audio board. So I can only comment on what's different from the original design and not what makes sense and what not.

Teensy
Connect all supply/gnd pins from the K20 (30,31,47,48).
no VREF_OUT capacitor (I think it's ok here to not connect VREF_OUT, because you don't use the DAC or ADC.)

On the Audio board (V2):
different cap values: C28, C32
R7, R2 resistors vs caps
pin 5 from the SGTL5000 is connected to 3.3V (through a ferrite bead). On your board it goes to +1.8V.

TPS61201
Connection from/to UVLO and VAUX doesn't look correct.
Click to expand...

Wow, that was great. I just spotted that teensy Audio Pin5 issue. Missed the Resistor ones and different caps values. Thanks a lot.
 
04-12-2015 09-17-34.jpg04-12-2015 09-21-20.jpg

I have modified the schematic. Anyone find anything that could cause some issues with this custom teensy 3.2 board?

Please post it so I and other would know.
 
Why is there no capacitor in series with SGTL5000 LINEOUT_L?

Do C11 and C13 connect anywhere? I find these schematics using net names for connections quite difficult to follow.
 
Also, you might look carefully at the specs for larger value capacitors in 0402 size. Make sure you've getting X7R or X5R types. Even then, with DC bias those tiny sizes tend to derate capacitance faster. Buyer beware.
 
Great!

Regarding C11, it is connected to the microphone line on the RN52 and C13 is connected to the left speaker line of the RN52.

This may appear counter-intuitive. The speaker line (SPK_L+) from RN52 is acting like a microphone/LINEIN_L to the SGTL5000, hence the C13.

While the SGTL5000 LINEOUT_R speaker line is acting like a microphone (MIC_L+) to RN52.

This is the flow diagram.

04-12-2015 12-48-47.jpg


About the 0402 capacitors, consider me informed. Will keep a close eye on it.
 
PaulStoffregen said:
Ok. You've prototyped and tested this with parts added to regular audio board, right?
Click to expand...

Yes Paul.

I tested it with Teensy 3.1, teensy Audio board and the RN52 audio Bluetooth breakout board in this configuration.
Strange thing was that, the setup appeared to be more stable when the RN52 microphone negative pin was left unconnected. Same for the Speak Pin.

The picture below is mad mash of the connections. As you can see I had more than required teensys but did that so I can configure the RN52 using uarts which would be tricky with the Audio board in place.

Notice the negative pins are not connected on the RN52 breakout board.

teensy-rn52-audio-board.jpg
 
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headset-pcb-pic 064.jpg

I am not sure what I am doing wrong. The board is not being recognised by the PC. The bluetooth module does show up on my phone. I did probe it with for activity, it does appear to have all the activity described on this site: http://www.appfruits.com/2015/03/building-your-own-custom-teensy/.

When I press the program button, nothings happens sometimes while at other times the led goes off, only coming back on when I unplug the USB and plug it back in.

Any ideas on how to diagnose the issue.
 
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experion said:
View attachment 6699

I am not sure what I am doing wrong. The board is not being recognised by the PC. The bluetooth module does show up on my phone. I did probe it with for activity, it does appear to have all the activity described on this site: http://www.appfruits.com/2015/03/building-your-own-custom-teensy/.

When I press the program button, nothings happens sometimes while at other times the led goes off, only coming back on when I unplug the USB and plug it back in.

Any ideas on how to diagnose the issue.
Click to expand...



still trying to figure out what I have done wrong. Paul, any ideas.
 
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